Video game TV tie-ins are different - or at least they can be. To prove the point, here are our Top 5 TV spin-off games for iPhone.

The Walking Dead TV series is itself a spin-off of a critically acclaimed comic book, which is perhaps why this iOS game tie-in was received with open arms. The other reason is that it's made by point-and-click adventure specialist Telltale Games. What we have here, then, is a completely fresh five-part story with original characters and some tricky moral decisions to make.

Showtime's edgy Dexter has been a bit of an unlikely hit, somehow making a likeable protagonist out of a serial killer. Dexter the Game's success is far more predictable. In it, you actually step into the shoes of forensic blood spatter analyst Dexter, carrying out case work to analyse crime scenes and locate your villainous victims. Killer stuff.

Everyone loves The Simpsons, don't they? Maybe it's gone off the boil in recent years, but like a long-beloved international star who develops a few wrinkles, we remember it for its golden years. The Simpson: Tapped Out is pretty golden itself, for it allows you to rebuild Springfield from scratch and send your favourite characters on epic quests.

One of the most influential TV shows of recent times, 24 showed how TV could rival the cinema for blockbuster thrills. Digital Chocolate's 24: Special Ops doesn't quite match the source material for widescreen spectacle, but it does let you tap into Jack Bauer's exhaustive skill set (from taking down bad guys to code breaking and bomb disposal).

Family Guy's crude humour isn't everyone's cup of tea, I grant you, but don't let that cloud your opinion of this rambunctious iOS tie-in. Genuine fans of the show, by the way, will love the in-jokes and faithful art style on display throughout this collection of mini-games. Help Brian escape Stewie's relentless assault, guide Quagmire in his attempts to 'make it' with Lois, and more.